How to Replace Alternator on a Tercel Wagon

I lent my car to my parents this summer, so it wouldn’t sit and rot while I rode my motorcycle instead. It is an old car – it has a few eccentricities. For instance, the first week after I bought the car last year, I lost my key. Since it’s an old Toyota, it isn’t difficult to break the ignition in such a way that you can turn the car on with a screwdriver. Old Toyotas are basically DOS boxes – security is an afterthought.

Soon after that I replaced the key, but the ignition lock slides in and out easily enough. This can be confusing for people who aren’t used to the car. When my mom started complaining that the car occasionally wouldn’t start, I assumed this was the problem. I told her to make sure she turned the lock all the way off, and didn’t leave it in ACC mode, killing the battery overnight. She insisted that she hadn’t done that, and that something was wrong with the car. After a couple weeks of balking, I went over to check it myself.

The car started fine, though I had to jump it off my dad’s car. I drove around the neighborhood, listening for noises and charging the battery. Once in a while, lights would flicker on the dashboard. Suspicious. I went home and parked it, then tried to restart it. Nothing, dead. Sat there stewing for a few seconds, then tried again. It started fine.

At this point I suspected electrical trouble. This article has a few methods for detecting alternator problems – I borrowed my brother’s multimeter and tried a couple of them, but I wasn’t able to prove anything to my satisfaction. So the next day I went to a dealership I used to work at and got a mechanic to run a diagnostic check. For 80 bucks to get a diagnosis of “yep, it’s busted” , I have to recommend that you learn to do electrical diagnosis yourself. But for me it was worth it to be sure that both the alternator and the battery were bad.

The service advisor quoted me $561 for a new alt, battery and installation. When he got to “$245 for the battery, a good one, installed”, my eyes crossed and I squeaked, “Erm, thanks very much but I believe I’ll do the work myself.”

Instead I got both the alternator AND the battery, from Lordco, for $240 total, and was able to do the job in about 2 hours. It wasn’t too tough at all. Here is an illustrated guide, relevant to the 1987 Toyota Tercel FWD Wagon (3AC), and probably every other Toyota of that decade as well.

How to Replace an Alternator on an Old Toyota

First, confirm that the alternator is the problem. You can do tests like the ones described here: Check An Alternator, or take the easy way out and get a tech to look at it.

It’s definitely the alternator, and the battery as well. Next, acquire parts.

Ouch. Well, could be worse. Ok, battlestations.

If you have a pdf or hard copy of the 1985 4wd Tercel Manual, now is a good time to pull it out. Here is a rather sketchy link to download it. If that doesn’t work and you honestly can’t find it yourself, email me.

Have a look at what the motor looks like before hand, so you know what it should look like when you’re done.

The black motor in the center bottom of the pic is for an aftermarket cruise control. It doesn’t work and isn’t actually connected to the engine, so I ripped it out.

Two bolts hold the alternator in place. This one, the adjusting bolt, needs a 12mm wrench:

And this is the pivot bolt, underneath the alt, 14mm.

Take note of the position of that top bolt, as it will help you adjust the new alternator to the correct spot. Don’t clean off the grime. It helps.

Remove the old battery.

Remove the positive terminal wire from the alternator, with a 10mm wrench. Unplug the plug at the back.

Loosen the adjusting bolt and the pivot, put them somewhere safe, and tug the thing out.

Old alternator pics, in case anyone needs them:

Toyota alternator info plate

Toyota alternator 3 prong plug

Pivot bolt

And here’s the new one, ready to go in:

When you install it, put the pivot bolt in first. Snug it but don’t tighten. Then put the adjusting bolt in. In my case, the entire engine had sagged, so that the bracket that the adjusting bolt goes through wouldn’t line up with the bolt hole. I put the old battery back in to for a fulcrum, and used a crowbar to lever the whole thing up a few millimeters.

See how it doesn’t line up?

Put the belt into its tracks, making sure it’s seated correctly on all three pulleys. Have a buddy use a crowbar to put tension on the alternator so you can tighten the bolt into the correct spot.

Belt in pulleys, no tension

I thought the adjusting bolt would have a lock nut on the back, but mine must have gone missing along the way somewhere. Then I stripped the threads in the bolt hole, so I couldn’t tighten it at all. At this point I took a quick break for a trip to Canadian Tire and got a couple of new nuts, bolts and washers.

Plug the plug back in, bolt on the positive terminal, and give it a try.

My cousin Darren, who is a first year automotive apprentice, says that a good way to check the tension is to try to turn the belt over with your fingers. If it turns all the way over, it’s loose. If it doesn’t turn at all, it’s tight. It should turn about halfway over. However, I am going to take it into a shop to double check my work on Monday, because the engine idle was pretty uneven after I started it back up.

Update: It just needed some spark plugs as well. Running fine now.

Mom and Dad standing ready with the fire extinguisher, before first test start.

Parts needed:

1 battery

1 alternator

1 M8 bolt, nut, and 2 washers

Tools needed;

14mm socket wrench

14mm crescent wrench

12mm socket

12mm crescent

10mm crescent

Hammer

Crowbar

Phone camera, for social media credits

Shop manual

Don’t forget to turn your old alternator and battery in for recycling.